playImg1 = new Image(30,30);
playImg1.src = "images/play_btn-over.gif";
playImg2 = new Image(30,30);
playImg2.src = "images/play_btn.gif";
downImg1 = new Image(30,30);
downImg1.src = "images/down_btn-over.gif";
downImg2 = new Image(30,30);
downImg2.src = "images/down_btn.gif";


function rollImage(imgDocID, imgObjName) {
document.images[imgDocID].src = eval(imgObjName + ".src");
return true;
}